The notion of stability is central to the definition of personality traits, which are generally thought of as enduring tendencies or habitual patterns of behavior, thoughts, and emotions (McCrae &Costa, 2003), stability does not imply immutability. Under normal circumstances, adult traits are largely stable, as indicated by high correlation coefficients computed for a group assessed twice on the same trait. These coefficients represent the average stability for a sample, but individuals vary in terms of their intra-individual stability. Recently, a longitudinal intra-individual approach was used to examine stabilities across two successive intervals traced within individuals. Individual stability coefficients from three sequential assessments were computed to evaluate intra-individual (i.e., within-person) change in stability over time. For both trait and profile (ipsative) stability, results indicate that intra-individual stability increases up to age 30 and then plateaus. Neither demographic variables (sex, ethnicity, education, and secular trends), nor the standing on the five major dimensions of personality, were predictors of change in trait stability. Contrary to results from studies of adolescents, personality maturity was unrelated to personality stability in adulthood. These findings support the notion that personality stability plateaus early in adulthood. Despite the relative stability of individual differences, in recent years we have extended the studies of mean-level change in personality by examining longitudinal trajectories in more diverse samples and cross-sectional trends across cultures. We have also focused on community or epidemiological investigations to study the causes of the modest changes that occur in personality traits in adulthood. Recent studies have examined the presumed reciprocal relation between experiences at work and personality: characteristics of the working environment are thought to contribute to personality development and, likewise, personality is thought to shape the daily realities of the job. Yet, few studies have measured both personality and the working environment at two points in time to explicitly test this reciprocal relation. In an economically-diverse community sample we found that as individuals progress through their careers in mid-life, they mold their everyday experiences on the job to fit their personality. Everyday working experiences, however, largely do not shape personality or strengthen corresponding aspects of the individuals personality. In related research, we addressed the dynamic transaction between extrinsic (occupational prestige, income) and intrinsic (job satisfaction) career success and personality. We found participants high in Neuroticism or low in Conscientiousness reported lower annual incomes and lower job satisfaction. Our longitudinal analyses revealed that, among younger participants, earning a higher income at baseline predicted decreases in Neuroticism across the 10 years between baseline and follow-up and higher levels of Extraversion predicted increases in income over this time period. The present findings implicate one aspect of the environment in personality development: those who earn higher incomes decrease on Neuroticism. It is of note that it is not how much one enjoys his job or the everyday realities of the working environment that contributes to personality development, but rather the material rewards of the job. Both personality and career success have been hypothesized to mutually influence each other across the lifespan. The current research suggests that this dynamic transaction may be limited to income and may only occur early in the career when both personality and careers are in flux. Retirement is a major normative life transition which profoundly affects patterns of everyday activities and social network composition. The present study examines personality as a predictor of retirement, patterns of longitudinal personality change associated with retirement, and personality correlates of retirement outcomes. Longitudinal analyses (n=367) compared personality trajectories of participants who remained employed and participants who retired. Personality at baseline did not predict future retirement, but compared to participants who remained employed, retirees increased in Agreeableness and decreased in Activity, a facet of Extraversion. In cross-sectional analyses among retirees (n=144), those low in Neuroticism and high in Extraversion reported higher retirement satisfaction and those high in Extraversion reported higher post-retirement activity levels. Findings suggest that the trait perspective contributes to our understanding of the retirement process. To further understand the biological underpinning of personality traits, in recent years we have examined the neural correlate of the major dimensions of personality, in particular Neuroticism and Openness. The trait Openness to Experience captures individual differences in cognitive flexibility, need for variety, and depth of emotional experience. Although open individuals score high on neuropsychological tests that assess function of the dorsolateral prefrontal cortex (DL-PFC), there is no direct evidence for the association between Openness and activity in specific brain regions. Using resting-state PET from 100 older individuals (>55 years of age), we identified associations between Openness and resting-state regional cerebral blood flow (rCBF) that replicated across two assessments of the same sample, approximately two years apart. Higher Openness scores correlated positively with resting-state rCBF in the dorsolateral prefrontal cortex (DL-PFC), the anterior cingulate (ACC), and in the orbitofrontal cortex (OFC). These relations were both specific and common across the sexes: Openness correlated with regions of the brain related to working memory for women (DL-PFC), attention and reward for men (ACC), and emotional and reward processing for both sexes (OFC). It is striking that Openness correlated positively with brain regions linked to working memory and attention as these are the two executive functions crucial for the core characteristic of Openness to Experience cognitive flexibility. It is also notable that these relations were sex-specific;this divergence suggests that the two sexes rely on different neural pathways for the operations that define the trait Openness to Experience.